let str = new String()    //包装类 --- 字符串对象
let s = ''     //字符串字面量

console.log(str);


// let n = new Number()
// let num = 0

// let b = new Boolean()

// let obj = new Object()

// let arr = new Array()

// let fn = new Function()
// function fn() {

// }
let date = new Date()

console.log(date);
